This invention relates generally to flat panel display devices and particularly to a color selection electron beam guide assembly for such devices.
U.S. Pat. No. 4,117,368 to F. J. Marlowe discloses a flat panel display device in which a backplate and a faceplate are spaced in parallel planes. A plurality of vanes extend between the backplate and faceplate to divide the envelope into a plurality of channels and to support the faceplate and backplate against atmospheric pressure after the envelope is evacuated. Arranged in each of the channels is a pair of spaced apart parallel beam guide meshes which extend longitudinally along the channels and transversely across the channels. The beam guide meshes serve as guides along which electron beams are propagated the lengths of the channels. Color displays can be produced by propagating three electron beams, one for each of the primary colors red, green and blue, in each channel.
The inside surface of the faceplate is provided with a phosphor screen which luminesces when struck by electrons. When a color display is to be produced, the screen includes three phosphors each of which emits one of the three colors of light. A plurality of extraction electrodes are arranged along the backplate and are used to eject the electron beams from between the beam guide meshes to direct the electron beams toward the phosphor screen. Deflection electrodes are provided on the sides of the support vanes and are electrically energized to cause the electron beams to transversely scan the channels. Accordingly, each of the channels contributes a portion of the total visual display of the device.
U.S. Pat. No. 4,131,823 to T. L. Credelle, discloses a structure for converging the electron beams at the shadow mask of a flat panel display device of the type described in the Marlowe patent. In the Credelle patent, convergence electrodes are provided on the support walls to cause the three electron beams to converge at the shadow mask.
The inventions described in the above-referenced patents are quite satisfactory for the purposes intended. However, the generating of a color display requires that three electron beams propagate in each of the channels and, accordingly, each channel must include three electron guns and the electron beam propagation structures must be capable of simultaneously propagating three electron beams. Additionally, the electron beams should be converged at a color selection shadow mask and the converged beams must be scanned transversely across the channel. For these reasons, such a display device is quite complex. Accordingly, it would be highly advantageous if a color display could be produced utilizing a single electron beam in each of the propagation channels.
The instant invention fulfills this need by the provision of a color selection electron beam guide assembly wherein a color display is produced utilizing a single electron beam in each channel of the display device.